Improving hole extraction for PbS quantum dot solar cells

Colloidal quantum dots (CQDs) are promising candidates for low-cost and high efficiency light harvesting materials owing to their solution processability and bandgap tunability. The most efficient lead chalcogenide QD solar cell reported to date is based on PbS, with a power conversion efficiency of 11.3%. However, in a typical QD cell, the hole transport layer has a much lower mobility than that of the ilayer, which hinders the hole extraction. In this work, we use Ag doped PbS QDs to form the p-type layer to increase its mobility and conductivity and significantly improve the device performance from 9.1% to 10.6% of power conversion efficiency.